Light load type push button switch

ABSTRACT

A light load type push-button switch comprises an actuator inserted at one end of movable-contact fixing section between fixed contacts opposing each other as secured to a housing and engaged at the other end of push-button contacting section to a push-button, said push-button contacting section having a spring section extending therefrom toward the movable contact fixing section, a supporting metal member as a common terminal and fixed to the housing so as to substantially transverse the actuator at a substantially intermediate position thereof, said spring section of the actuator being fixed to the supporting metal member at the free end of the movable-contact fixing section side, and a turning spring member, or toggle spring, engaged to the actuator for biasing the push-button contacting section thereof toward the push button.

United States Patent [1 1 Hoshioka Sept. 24, 1974 LIGHT LOAD TYPE PUSH BUTTON SWITCH Inventor: Hideoki Hoshioka, Osaka, Japan Matsushita Electric Works, Ltd., Osaka, Japan Filed: Apr. 26, 1973 Appl. No.: 354,699

Assignee:

Foreign Application Priority Data Apr. 28, 1972 Japan 47-50407 June 22, 1972 Japan 47-74213 References Cited UNITED STATES PATENTS Primary Examiner-David Smith, Jr. Attorney, Agent, or FirmWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[5 7 ABSTRACT A light load type push-button switch comprises an actuator inserted at one end of movable-contact fixing section between fixed contacts opposing each other as secured to a housing and engaged at the other end of push-button contacting section to a push-button, said push-button contacting section having a spring section extending therefrom toward the movable contact fixing section, a supporting metal member as a common terminal and fixed to the housing so as to substantially transverse the actuator at a substantially intermediate position thereof, said spring section of the actuator being fixed to the supporting metal member at the free end of the movable-contact fixing section side, and a turning spring member, or toggle spring, engaged to the actuator for biasing the push-button contacting section thereof toward the push button.

5 Claims, 9 Drawing Figures PAIENTED 3.83%237 SHEET Q ,PRIOR ART \f t A 4 ,PORCE OF SPRINC 5 LQ SECTION l6 ITS PRESULTANT PUSH BOTTON E O OPERATING LOAD Z O Q /EORCE OF TURNIN 3 SPRING 2I l Z1 PRESSURE O :3 NORIIAAEEY CLOSED CONTACT LL] g \I O I (5 N-PRESSURE ON NORMALLY 5 O ENED CONTACT TLC PUSH BUTTON STROKE LIGHT LOAD TYPE PUSH BUTTON SWITCH This invention relates to small switches and, more particularly, to a microswitch in which a high contact pressure can be obtained with a light load.

In conventional microswitches of this kind, as exemplified in FIG. 1 showing an example schematically, a handle supporting member 30 and an actuator 31 are made respectively of separate parts and, therefore, the contact at hinging points 32 and 34 has been unstable. Further, as the return motion of the actuator 31 has been performed with the force of only a turning spring 33 engaged to the actuator, no high contact pressure has been able to be obtained.

The present invention has been suggested to solve the above mentioned problems by using an actuator having a handle section and return spring section in one spring plate.

A main object of the present invention is, therefore, to provide a microswitch of a high contact pressure with a low load by using a smaller number of component parts.

Another object of the present invention is to provide a microswitch wherein the actuator is provided with a spring section so that the instability of the contact at conventional hinging points are eliminated.

A further object of the present invention is to provide a microswitch in which the mass around the contact part is small and the shock-proofness is excellent.

Now the present invention shall be explained with reference to the accompanying drawings, in which:

FIG. 1 is a schematic sectioned view of an exemplary one of conventional microswitches;

FIG. 2 is a sectioned view of a microswitch of the present invention;

FIG. 3 is a perspective view of essential parts of the microswitch of FIG. 2 as disassembled;

of which is adapted to be a push button contacting section. From this push button contacting section, as the base, a spring section 16 extends toward the movable contact fixing section. These push button contacting section and spring section 16 are forming a handle section of the actuator 12. Further, a hole 17 is provided adjacent free end of the spring 16 at the side directed to the movable contact fixing section and extensions, or side springs, 18 and 19 are provided at both sides of the free end as branches therefrom and reverse directed to the push button contacting section side. At the respective outer sides of these extensions 18 and 19, there are provided notches 20 and 20. A projection is pro- FIGS. 4A to 4C are diagrams showing operating states of the microswitch according to the present invention;

FIGS. 5A and 5B are diagrams for explaining the operations of the same; and

FIG. 6 shows pressing load and contact pressure curves with respect to push button stroke.

In FIGS. 2 and 3, a case or housing 1 forms a substantial body of the microswitch, to which a terminal plate 2 provided at an end with a normally closed contact 3 and another terminal plate 4 provided at an end with a normally opened contact 5 are fixed so as to extend at the respective other ends out of the housing 1 and to have the respective contacts 3 and 5 opposed to each other above and below. As a common terminal, a supporting metal member 6 bent substantially in Z-shape is fixed to the housing 1 in such that an upper part 7 is embedded in an inside wall of the housing and the other lower part 8 is extended out of the housing downward. The supporting metal member 6 is formed to have an inverted T-shaped engaging hole 9 in the bent section located substantially in the middle, a notch 10 on each side of horizontal section adjacent the bent section and a locking arm 11 projecting laterally at each side of vertical section adjacent the bent section. Inside the housing 1, there is disposed an actuator 12, an end of which is adapted to be a movable contact fixing section having a normally closed movable contact 13 and normally opened movable contact 14 fixed respectively to upper and lower surfaces thereof and the other L-shaped end vided downward in the base part of the movable contact fixing section side. A turning spring member, or toggle spring, 21 formed in C shape for compressive action is separately prepared, so as to be provided with a locking extensions 23 and 23' at one end and with an engaging slot 24 at the other end. For manually operating the actuator 12, a push button 25 made of an insulative material is provided.

Now the assembly of the microswitch of the present invention shall be explained. The actuator 12 is fixed to the supporting metal member 6 preliminarily fixed to the housing 1, in such manner that the hole 17 will be fitted to a stubby projection 26 provided at lower surface of the horizontal section of the supporting metal member 6, and the projection 26 is calked to tightly secure the free end of the spring section 16. Then, the turning spring member 21 is fitted to the actuator 12 from above in such that the engaging slot 24 of the turning spring 21 is engaged to the downward projection 15 of the actuator 12 and then the locking extensions 23 and 23 of the turning spring 21 are respectively inserted into the notches 10 of the supporting metal member 6 and further into the notches 20 and 20 of the extensions 18 and 19 in the spring section of the actuator 12, so that the locking extensions 23 and 23 of the turning spring 21 will engage in the notches 20 and 20', respectively. The push button 25 is slidably disposed so as to be in contact with the other end of the actuator 12, that is, the push button contacting section.

The operation shall be explained in the following with reference to FIGS. 4A to 4C. In the drawings, notations a, b, c, and d are used for representations of the following points. That is, the point a represents a point of engagement of the projection 15 of the actuator 12 with the turning spring 21 at the engaging slot 24. The point b represents a point on the actuator 12 at which the operating load from the push button 25 is received at the other end of the actuator. The point c represents a point of engagement of the locking extensions 23 and 23 of the turning spring 21 with the extensions 18 and 19 at their notches 20 and 20' in the spring section 16 of the actuator 12. The point d represents the fixing point at which the spring section 16 of the actuator 12 is fixed by means of the projection 26 of the supporting metal member 6 through the hole 17 in th spring section 16 of the actuator 12.

In the actuator arrangement as above, the respective points a, b, c and d are positioned under normal or nonactuated condition, substantially in the same plane, and the points c and d will keep their relative positions which are shifted slightly up and down with respect to the part ab of the actuator 12 which is moved up and down depending on a stroke of the point b given by the actuated push button 25. Further, the spring section 16 between the points b and d acts as a return spring for the actuator 12 since the point d is a fixed point.

In the state where the push button is not pushed (FIG. 4A), the point b is at the uppermost position and the point remains in its position below 55. Therefore, an upward component force FI-I due to the turning spring 21 will be added to the contact pressure directed to the normally closed fixed contact 3, whereby the normally closed movable contact 13 will be additionally urged into contact with the fixed contact 3.

Further in this state, the point d is positioned below a 5 and, therefore, the handle section of the actuator 12 is subjected to an upward moment caused by a component force in the direction of 55 due to the turning spring 21 (the state corresponds the push button stroke point A in FIG. 6). At this time, the returning force of the spring section 16 itself will be zero.

When the push button is gradually pushed until ab reached the point c, as shown in FIG. 4B, the component force relating to the contact pressure due to the turning spring 21 will vanish, the contact pressure of the normally closed movable contact 13 against the normally closed fixed contact 3 will become zero and thus the actuator 12 enters into the state immediately before the turning or switching movement.

On the other hand, in this state, the point d is still positioned below 55 and the moment to which the handle or spring section 16 is subjected due to the turning spring 21 will remain but with a reduced amount.

At this time, however, the returning force of the spring section 16 itself will increase and the resultant force (the curve of which is represented in FIG. 6 as the resultant push button operating load) of both the moment to which the handle or spring section 16 is subjected due to the turning spring 21 and the returning force of the springsection 16 itself substantially will not vary (the state corresponds to the stroke point B in FIG. 6).

Next, when the push button is further pushed dow nward from the above mentioned state andmasses through the point 0 so as to be shifted below it, as shown in FIG. 4C, the component force FH in the direction relating to the contact pressure due to the turning spring 21 will be directed downward in this state, so that the normally opened movable contact 14 will be brought into resilient contact with the normally opened fixed contact 5.

In this state, further, the point d will be positioned above 55. In such case, the spring section 16 will be subjected to a downward moment by the turning spring 21 but the returning force of the spring section 16 itself will further increase and, therefore, the resultant push button operating load due to the return spring moment and the spring section returning force will be maintained at a value larger than zero (the state corresponds to the stroke point C in FIG. 6).

On the other hand, in the conventional switches as exemplified in FIG. 1, the returning force of the actuator depends solely on the turning spring 33 and, therefore, the required returning force becomes excessive as shown by a broken lines in FIG. 6 in order to provide a self-returning type switch and, on the other hand, the contact pressure becomes a smaller value comparing with the required push button operating load.

Now, the action of the extensions 18 and 19 of the spring section 16 in the actuator 12, that is, the spring force caused by the part FJshall be explained with reference to FIG. 5A and 5B.

In the drawings, the arrangement in general conventional switch is represented by broken lines and with dashed notations, and the arrangement according to the present invention is represented by solid lines and with nondashed notations.

In the switch according to the present invention, the engaging point c of the turning spring 21 and actuator 12 is disposed in the free end part of the extensions 18 and 19 extending from the fixed point d and the extensions 18 and 19 will flex to move the engaging point 0 in the direction of enlarging the angle 0 defined by the actuator 12 and the force line direction of the turning spring 21, due to the spring force of the turning spring 21. Therefore, the component force FH relating to the contact pressure will be increased to be larger than FH' in the case of the prior art, that is, the contact pressure will be increase by FI-I-FI-I.

This action is performed in both states of the actuator in which the same is in the normally closed contact side (FIG. 5A) and in the normally opened contact side (FIG. 53), so that the contact pressures on both the normally closed side and normally opened side will be increased in the same manner.

The operation of the switch described above may be summarized as follows: The point of support 26 is intentionally non-symmetrical with respect to the two contacts and the handle portion b is similarly offset with respect to the contacts so that the toggle angle is inclined upwardly to cause the contact section to bear against the upper one of the contacts as shown in FIG. 2.

However, when the push button is depressed, flexure takes place in the central spring and the two side members of the actuator spring move bodily downward thereby reversing the toggle angle so it has a downward slant, or component, thereby bringing the contact section into engagement with the lower contact. Because of the support provided at 17 and the presence of the auxiliary spring member 18, 19 the actuating force, as stated above, is much less than that usually required in a switch of comparable current carrying capacity. Releasing the push button enables the mechanism to restore itself to the condition shown in FIG. 2.

While the invention has been described in connection with a single-pole, double-throw switching function, it will be apparent that one of the main purposes of the elements 3, 5 is to serve as limit stops, and only one of such elements need be an electrical contact.

What is claimed is:

1. A small switch comprising a housing, a push button mounted therein, an actuator in the form of a leaf spring having a push button contacting section and a movable contact section at respective ends, said push button contacting section being provided with a spring section branched from the contacting section as a base and having a free end extending toward said movable contact section, a supporting metal member fixed within said housing, said actuator being fixed at said free end of the spring section to said supporting member, a turning spring member engaged with the actuator, movable contacts fixed to the contact section of the actuator, a normally closed fixed contact and normally open fixed contact mounted in the housing and opposed respectively to said movable contacts, the turning spring being interposed between the contact section of the actuator and a receiving part on the spring section of the actuator, the turning spring receiving part comprising an extension of the spring section of the actuator, said extension being branched from the free end of said spring section and directed toward the push button contacting section of the actuator.

2. A small switch of the micro type comprising. in combination, an actuator in the form of a generally flat leaf spring having a handle section at one end and a contact section at the other, the sections being interconnected by spaced integral side members defining a central space, the actuator having an integral central spring in the central space extending from the handle section, a housing, a supporting member centrally positioned in the housing, the end of the central spring being secured to the supporting member, the housing providing closely spaced stops for limiting movement of the contact section in both directions, at least one of the stops being in the form of an electrical contact, a toggle spring member of C shape having one end engaged with the central spring and the other end engaged with the contact section so that force applied to the handle section moves the toggle spring over center for snapping of the contact section between its alternate positions.

3. The combination as claimed in claim 2 in which the supporting member is located at a level which is non-symmetrical with respect to the stops to establish a normal toggle angle causing the contact section to noramlly contact one of the stops and in which a push button is provided for pressing on the handle section to re-' verse the toggle angle for throwing of the contact section to its alternate stopped position.

4. The combination as claimed in claim 2 in which the central spring includes auxiliary leaf springs extending toward the handle section from adjacent the region of support, one end of the toggle spring engaging the ends of the auxiliary springs.

5. A small switch of the micro type comprising, in combination, an actuator in the form of a generally flat leaf spring having a handle section at one end and a contact section at the other, the sections being interconnected by spaced integral side members defining a central space, the actuator having a central leaf spring in the central space which extends from, and forms a continuation of, the handle section, a housing, a supporting member centrally positioned in the housing, the supporting member being secured to the end of the central spring, the housing providing closely spaced stops for limiting movement of the contact section in both directions, at least one of the stops being in the form of an electrical contact, the central spring having an integral extension extending reversely toward the handle section, a toggle spring member of C shape having one end engaged with the extension on the central spring and the other end engaged with the contact section, the support and the handle portions both being located non-symmetrically with respect to the stops so that the contact section normally bears against one of the stops to establish a normal toggle angle, and means for operating the handle member to reverse the toggle angle to throw the contact section to the alternate stop. 

1. A small switch comprising a housing, a push button mounted therein, an actuator in the form of a leaf spring having a push button contacting section and a movable contact section at respective ends, said push button contacting section being provided with a spring section branched from the contacting section as a base and having a free end extending toward said movable contact section, a supporting metal member fixed within said housing, said actuator being fixed at said free end of the spring section to said supporting member, a turning spring member engaged with the actuator, movable contacts fixed to the contact section of the actuator, a normally closed fixed contact and normally open fixed contact mounted in the housing and opposed respectively to said movable contacts, the turning spring being interposed between the contact section of the actuator and a receiving part on the spring section of the actuator, the turning spring receiving part comprising an extension of the spring section of the actuator, said extension being branched from the free end of said spring section and directed toward the push button contacting section of the actuator.
 2. A small switch of the micro type comprising. in combination, an actuator in the form of a generally flat leaf spring having a handle section at one end and a contact section at the other, the sections being interconnected by spaced integral side members definIng a central space, the actuator having an integral central spring in the central space extending from the handle section, a housing, a supporting member centrally positioned in the housing, the end of the central spring being secured to the supporting member, the housing providing closely spaced stops for limiting movement of the contact section in both directions, at least one of the stops being in the form of an electrical contact, a toggle spring member of C shape having one end engaged with the central spring and the other end engaged with the contact section so that force applied to the handle section moves the toggle spring over center for snapping of the contact section between its alternate positions.
 3. The combination as claimed in claim 2 in which the supporting member is located at a level which is non-symmetrical with respect to the stops to establish a normal toggle angle causing the contact section to noramlly contact one of the stops and in which a push button is provided for pressing on the handle section to reverse the toggle angle for throwing of the contact section to its alternate stopped position.
 4. The combination as claimed in claim 2 in which the central spring includes auxiliary leaf springs extending toward the handle section from adjacent the region of support, one end of the toggle spring engaging the ends of the auxiliary springs.
 5. A small switch of the micro type comprising, in combination, an actuator in the form of a generally flat leaf spring having a handle section at one end and a contact section at the other, the sections being interconnected by spaced integral side members defining a central space, the actuator having a central leaf spring in the central space which extends from, and forms a continuation of, the handle section, a housing, a supporting member centrally positioned in the housing, the supporting member being secured to the end of the central spring, the housing providing closely spaced stops for limiting movement of the contact section in both directions, at least one of the stops being in the form of an electrical contact, the central spring having an integral extension extending reversely toward the handle section, a toggle spring member of C shape having one end engaged with the extension on the central spring and the other end engaged with the contact section, the support and the handle portions both being located non-symmetrically with respect to the stops so that the contact section normally bears against one of the stops to establish a normal toggle angle, and means for operating the handle member to reverse the toggle angle to throw the contact section to the alternate stop. 